There seems to be a lot of stuff on the forums about flight controllers, yet nothing that addresses my question. I have totaled a couple of flite test planes now and have decided that i suck bad enough as a pilot that i need some help. I have a Tactic transmitter and receiver combo. The receiver has PWM outputs only. It seems most flight controllers use another type of input (UART, SBUS, PPM, etc.). I have found a few that use the PWM from the receiver directly, but they are either 3 axis only or are pretty pricey. I could buy a really cheap PWM-to-PPM encoder, but that's just one more thing to break and one more thing to add weight to the plane. I don't need any sort of RTH or baro hold or even GPS for that matter... just trying to make flying fun, which it's NOT at the moment. I'm only using 4 channels at the moment; 1 motor, 1 elevator, 1 rudder, and 1 aileron (wired in a Y config for roll only). I'd really like the flight controller to add a "flaps" function to the aileron channel but that means i'd have at a minimum a 5 output channel controller. I'm thinking I'd simply just use a 5+ input / 5+ output flight controller and just wire the 2 aileron channels using the Y harness i'm currently using. Any thoughts? Any pointers to a flight controller that would fit the bill? Should i just commit to the PWM-to-PPM encoder to open up options on the flight controller?
Another Flight Controller Help Request
- Thread starter giddo
- Start date
quorneng
Master member
My suggestion is to avoid a flight controller and use a gyro stab receiver that works on the Tactic transmitter protocol.
It simply replaces your existing rx, plug for plug, and provides stabilisation on elevator, aileron and rudder. The only issue is it has to be mounted appropriately as does any gyro system. The degree of stab can be set or, on some, if you you have the spare channels, it can be adjusted in flight or switched off completely.
It reacts to any disturbances far faster than you can so the plane just flies smoothly giving you the time & confidence to just control where you want to go.
It simply replaces your existing rx, plug for plug, and provides stabilisation on elevator, aileron and rudder. The only issue is it has to be mounted appropriately as does any gyro system. The degree of stab can be set or, on some, if you you have the spare channels, it can be adjusted in flight or switched off completely.
It reacts to any disturbances far faster than you can so the plane just flies smoothly giving you the time & confidence to just control where you want to go.
Very interesting... from the industry i work in, i am (vaguely) familiar with inertial navigation and the functions that IMUs (inertial measurement units) play. They are "6 axis" since you have 3-axis (x, y, z) acceleration and 3-axis (roll, pitch, yaw) rate measurements, the later which come from the gyros. I'm not familiar with, however, a gyro only system. Also, I'm less familiar with how an RC hobby "gyro system" differs from a "flight controller" when it comes to flight stability.
You are exactly correct that i want the "thing" that I'm buying to react quickly to perturbations in the flight environment that i am too slow to recognize and correct for. However, I am also looking for it to correct my deficiencies in piloting. For example, if i'm not commanding a roll, the plane shouldn't roll even if i'm commanding full throttle (which for a single prop plane, will always have a tendency to roll under full power). As it stands, i have to remember to command a counter roll when i increase the throttle--something that i'm not very good at doing. Likewise, as the plane slows down due to a throttle down condition, i'd like the "flaps" to limit the downward acceleration as much as possible while keeping the pitch well below a stall (unless i command such a pitch). Perhaps the "flaps" function i'm looking for is out of the norm for flight controllers or gyro systems. But using a 5th channel to separate the ailerons to allow a manual flap function would only mean another control channel that i would need to keep up with as a pilot--I can already tell you that will not work out well for me.
Lastly, i've been quite perplexed as to how these flight controllers can just be mounted any which way as I've always understood that the frame of an IMU must be aligned with the airframe or else a rotation matrix must be supplied to the autopilot loop. I just assumed that there was some sort of calibration that needed to be performed and the processor would create the translation matrix during that calibration step. Based on your post, that isn't the case. A gyro system needs to be mounted in alignment with the airframe. But what about a flight controller? Why doesn't it need to be aligned to the airframe? Is my assumption about the calibration step correct for a flight controller?
Sorry for the myriad questions. Any help is much appreciated and your response is already put me significantly ahead of where i was.
EDIT: So i found this on Amazon -
HOBBYEAGLE A3 Aeroplane Flight Controller Stabilizer System 6-axle Gyro for RC Drone Airplane Fixed-Wing Copter
I think I get the difference... the gyro stabilizer will give me most of what i'm looking for, stabilizing the roll pitch and yaw. So it will help with the roll due to throttle torque. Plus, it's PWM for both input and output, which is what i'm looking for. However, it will not implement the flap function. I'm starting to think that a flight controller will not help with that either as that is probably not a normal function folks are looking for. Also, the acceleration channels are not necessary since i'm not needing to keep track of where i'm at, only stabilizing the airframe (or filtering out unwanted roll, pitch and yaw). Since flight controllers usually also implement things like return to home, they need the acceleration channels to feed the navigation engine (Khlman filter??). Anyhow, thanks for the pointer. And any feedback/correction to my post would be beneficial and I'm sure helpful to others, so thanks in advance!
You are exactly correct that i want the "thing" that I'm buying to react quickly to perturbations in the flight environment that i am too slow to recognize and correct for. However, I am also looking for it to correct my deficiencies in piloting. For example, if i'm not commanding a roll, the plane shouldn't roll even if i'm commanding full throttle (which for a single prop plane, will always have a tendency to roll under full power). As it stands, i have to remember to command a counter roll when i increase the throttle--something that i'm not very good at doing. Likewise, as the plane slows down due to a throttle down condition, i'd like the "flaps" to limit the downward acceleration as much as possible while keeping the pitch well below a stall (unless i command such a pitch). Perhaps the "flaps" function i'm looking for is out of the norm for flight controllers or gyro systems. But using a 5th channel to separate the ailerons to allow a manual flap function would only mean another control channel that i would need to keep up with as a pilot--I can already tell you that will not work out well for me.
Lastly, i've been quite perplexed as to how these flight controllers can just be mounted any which way as I've always understood that the frame of an IMU must be aligned with the airframe or else a rotation matrix must be supplied to the autopilot loop. I just assumed that there was some sort of calibration that needed to be performed and the processor would create the translation matrix during that calibration step. Based on your post, that isn't the case. A gyro system needs to be mounted in alignment with the airframe. But what about a flight controller? Why doesn't it need to be aligned to the airframe? Is my assumption about the calibration step correct for a flight controller?
Sorry for the myriad questions. Any help is much appreciated and your response is already put me significantly ahead of where i was.
EDIT: So i found this on Amazon -
HOBBYEAGLE A3 Aeroplane Flight Controller Stabilizer System 6-axle Gyro for RC Drone Airplane Fixed-Wing Copter
I think I get the difference... the gyro stabilizer will give me most of what i'm looking for, stabilizing the roll pitch and yaw. So it will help with the roll due to throttle torque. Plus, it's PWM for both input and output, which is what i'm looking for. However, it will not implement the flap function. I'm starting to think that a flight controller will not help with that either as that is probably not a normal function folks are looking for. Also, the acceleration channels are not necessary since i'm not needing to keep track of where i'm at, only stabilizing the airframe (or filtering out unwanted roll, pitch and yaw). Since flight controllers usually also implement things like return to home, they need the acceleration channels to feed the navigation engine (Khlman filter??). Anyhow, thanks for the pointer. And any feedback/correction to my post would be beneficial and I'm sure helpful to others, so thanks in advance!
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The Hobby Eagle is a great system, there are several different versions to choose from. Find the one with the features you are looking for. Several versions have auto level, to return a plane to level flight if you get into trouble.
The stock setting require the stabilizer/flight controller to be installed a certain way. If it will not fit, you can change the orientation, then adjust the settings accordingly. The Hobby Eagle I have can be mounted virtually in any orientation.
quorneng
Master member
Giddo
A typical 'stab' receiver is a normal 6 channel unit so can perform all the same flap and gear functions. The gyros which can be 3 or 6 axis depending on the model only work on the elevator, aileron and rudder functions.
In principle the smaller and lighter the plane the faster it responds to outside influences so the bigger the 'calming' effect such a gyro system will have.
I can fly well enough but I do build very light foam planes and many true scale. As a result they are not the normal 'foam robust' so the benefit of a gyro rx, particularly on the maiden when the flight characteristics are unknown, is most valuable.
I always include the 'switch off in flight' option (it uses 1 channel) and do so once at sufficient height to find out how the plane really flies but keeping my finger near the switch just in case! The first few approach and landings will definitely have the gyro on.
As a gyro rx is literally a plug for plug identical to a normal rx once happy I usually change over and move the gyro unit on to my next build.
Any gyro will not make an unflyable plane fly but it greatly increases the chances that if it can it will and an FT plane built to specification can be expected to fly.
A typical 'stab' receiver is a normal 6 channel unit so can perform all the same flap and gear functions. The gyros which can be 3 or 6 axis depending on the model only work on the elevator, aileron and rudder functions.
In principle the smaller and lighter the plane the faster it responds to outside influences so the bigger the 'calming' effect such a gyro system will have.
I can fly well enough but I do build very light foam planes and many true scale. As a result they are not the normal 'foam robust' so the benefit of a gyro rx, particularly on the maiden when the flight characteristics are unknown, is most valuable.
I always include the 'switch off in flight' option (it uses 1 channel) and do so once at sufficient height to find out how the plane really flies but keeping my finger near the switch just in case! The first few approach and landings will definitely have the gyro on.
As a gyro rx is literally a plug for plug identical to a normal rx once happy I usually change over and move the gyro unit on to my next build.
Any gyro will not make an unflyable plane fly but it greatly increases the chances that if it can it will and an FT plane built to specification can be expected to fly.
randyrls
Randy
I'm only familiar with the Aura 5 Lite, It has an configurator (for Windows) that can change the orientation of the FC so you can mount the FC upside down or any which way. You then write the configuration to the FC. Many FC's have some way to change the orientation of the FC, but each one is different. Often the key is to power up the plane and sit the plane level on the ground. Hope this helps...
As far as stability in an airplane, there is not much if any difference between a flight controller and a gyro system. Both will do stability equally well in an airplane. A flight controller will do more advanced things, like return to home and flying a predetermined route. A flight controller may have stability advantages in a quad, which has far greater stability requirements than an airplane.
Many of the Hobby Eagle gyros feature, heading hold, auto level, a beginner mode which limits the pitch and roll, in addition to basic stability. They work with any PWM receiver, one that controls servos, and the setup is far easier than a flight controller.
If you plane is torque rolling or pitching under power, there is something wrong with your setup. A gyro system may mask over the underling problem but will not solve it. I would look to trim, CG, thrust angle or motor size to correct the problem. In an airplane, pitching and torque roll can be solved without a gyro.
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NickRehm
Member
If you already have some knowledge and want a lot more control over the internals (i.e. source code & custom mixing functionality), you can check out my flight controller that runs on a Teensy 4.0 w/ MPU6050 with code uploaded through the arduino IDE: https://github.com/nickrehm/dRehmFlight Might be a good fit you, though I will always recommend to build a good flying plane BEFORE trying to get fancy with onboard stabilization
Monte.C
...
Hey man I just came across your suggestion here by accident. I didn't know such a thing was available and it looks exciting. I've been toying with the idea of using this Hobbyeagle A3 I have, but I would want to use it more for smaller planes, and that costs more weight and more fuselage space that I don't have. AND to be able to turn it off would need a channel - which I don't have when I mix two motors to rudder function.
How is this "Admiral RX600SP 6-Channel DSMX Compatible Receiver" I found?
https://www.motionrc.com/products/a...mx-compatible-receiver-with-6-axis-stabilizer
PsyBorg
Wake up! Time to fly!
Any tape I have used with regards to flight controllers like in my OG Gremlin is simple 3m double sided tape. Its like rubber and sicky on both sides. Bonds great yet can easily be removed by wetting a q tip with alcohol and rubbing around the edges to get it to release.
Monte.C
...
Bam. Thanks, I've been wondering about that for a long time. Sorted.
Monte.C
...
What's OG. Something to do with tri's and quads?
I'd be afraid of dissolving the foam or at least the paper, but I think I know how to do it. These NY Transit subway cards are like credit cards but very thin. I can glue a piece of that inside the fuse, then mount/tape to that.
quorneng
Master member
Monte.C
"How do you move it from model to model?"
A stab rx is not that expensive so I tend to leave mine in until the crash is so severe (not so common with a stab
) that the plane is written off. Any gyro system is 'setup' to match the characteristics of the plane so moving it is not quite the same as moving a plain rx.
For the best possible stab performance I actually build mine in with a surrounding foam structure so it is held absolutely rigid to the airframe. If and when you have to move it the supporting structure is simply broken out. It is easily replaced/repaired if you want to put another receiver back in.
It works for me.
"How do you move it from model to model?"
A stab rx is not that expensive so I tend to leave mine in until the crash is so severe (not so common with a stab
) that the plane is written off. Any gyro system is 'setup' to match the characteristics of the plane so moving it is not quite the same as moving a plain rx.For the best possible stab performance I actually build mine in with a surrounding foam structure so it is held absolutely rigid to the airframe. If and when you have to move it the supporting structure is simply broken out. It is easily replaced/repaired if you want to put another receiver back in.
It works for me.
Monte.C
...
Yeah I got you.
I mean swabbing alcohol around inside my plane. Sure wouldn't want to ruin the plane, removing that gummy tape from a paper surface.
Or maybe the tape can stay in there and just remove the component from the tape...
randyrls
Randy
You could make a 3D printed holder mount. There is one on Thingiverse for the Aura 5 lite.
CampRobber
Active member
TBH products like the FT Aura seem like you're paying a huge premium for "easy". An F411Wing is $10 less than an Aura but includes more channels, accelerometers, current sense, barometer, ubecs, etc. You'll have to mess with inav configurator for a while to get to the Aura-out-of-box simple stabilization status, but from there you'll have a lot more future expandability.
Coderteam1
Member
multiwii flight controller
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